Grass-Fed Pork? Not Really. Still the Difference in Fatty Acid Composition & Micronutrient Content Are Profound & Not Accounted for by Food Databases - Let Alone Epidemiology

You often hear that pigs are pretty closely related to us humans, but "are all pigs created equal"? Or what may be a more appropriate question for the SuppVersity: Is all pork really created equal?

If you like databases like nutritiondata.com or the USDA's very own detailed nutrient database in order to evaluate whether your diet is actually delivering all the nutrients you need you are probably missing half of the picture. At least as far as the more sophisticated details go, a recent paper from the Instituto de Ingeniería de Alimentos para el Desarrollo at the Universidad Politécnica de Valencia clearly indicates that you would at least have to consider what the animals, in this case pork, were fed and from which muscle of the animal the piece of meat you are eating has been cut, in order to get an approximate idea of how much of unquestionably health relevant micronutrients, such as coQ10, carnosine, anserine, taurine, creatine glutamine or haem you get - and in some cases the differences can be way larger than 100%!

If pizza salami equals pork...

... in epidemiological studies, how can these studies on the fallacies and advantages of eating red meat, which usually get a hell lo of media attention, be accurate, given the fact that the amount of unquestionably beneficial coQ10, for example, would differ by 60 percent, even if you would only ignore the difference between loin that was cut from the trapezius (= high coQ10 content) and the longissimus dorsi (=low coQ10 content)?

Figure 1: Content of selected amino acids and micronutrients in cuts from different muscle; data expressed relative to respective mean (total value is given in mg/100g above the bars) of all tested muscle samples (data based on previous studies by the co-authors that have been compiled for Reig. 2013).

Moreover, if you take a look at the complete data in figure 1 it should be clear that coQ10 is only one of several micro-nutrients / amino acids that are highly dependent on which muscle your particular steak or whatever you are about to eat was cut from. Let's take taurine as yet another example. A prolonged low dietary intake of taurine has been observed to be linked to a number of disorders including retinal degeneration, retardation of growth and development, cardiovascular dysfunctions, CNS abnormalities, immune impairment and hepatic disorders (Abebe. 2011). If you eat meat (fish & other animal products) only occasionally and are therefore at risk of not getting adequate taurine in your diet, eating sausages from a butcher you trust would be a better choice than a piece of ham, since the former do include the high taurine meat from the masseter (cheeks) of the animals, while ham does not.

Let's get to the obvious: Grass-fed is... ah, wait a minute

"Grass fed is best" as you will people say about beef obviously won't be the case for pork, because pigs, just like humans, by the way, are omnivores. The simple formula, grass-fed = most beneficial fatty acid and micronutrient profile that may (in general) be valid for beef doesn't apply and we will have to take a closer look at the actual data first to decide what would be the "best" feed for pigs, if the goal was not a maximal yield of lean meat (in that case adding some clenbuterol, like the Chinese like to do it would be the least you should do; cf. The China Post. 2011), but rather to produce the meat with the most beneficial fatty acid  composition.

Figure 2: Fatty acid composition (primary axis) and omega-6 to omega-3 ratio of pork from pigs fed different diets (corrected version of data Reig et al. re-pupublished based on previous studies; spec. the figure for the n6:n3 ratio in the "standard feed" group that's based on Enser et al. was off - a ratio of 1.54 is obviously unrealistic)

I we define "most healthy" as having the lowest omega-6 to omega-3 ratio - a practice that seems appropriate given that 95% of the inhabitants of the so-called 'Westernized World' consumes way too much of the former and (comparably) way too little of the latter type of polyunsaturated fatty acids, the data in figure 2 clearly argues in favor of *surprise* the standard feed - at least if you define that by the feed the animals the meat of which (50 samples) Enser et al. bought in British supermarkets in 1996 (note: these values are still higher than for the conventional beef samples from the same study, which had a n-6:n-3 ratio of ~2.2; cf. Enser. 1996). There are however more intricate patterns that are not evident from the overview in figure 2, but could have implications as far as the direction into which "pork production" could or should head to in the future is concerned (summarized based on Reig. 2013):

Do you notice a pattern? I guess even based on the data in figure 2 you will already have noticed that the "grainier" the diet, or in other words, the more corn and soy there is in the diet of the swine the less favorable is the fatty acid composition of their meats going to be. Now, I am asking an outrageous question: If swine are such a good model for human metabolism, what do you believe your belly was going to be made of, if you copied the pigs' diets and lived on "healthy grains", their oils and the uber-healthy soy beans for the (probably pretty short) rest of your life?
• more food (yet no excess) can produce overall leaner muscle meat in the type II fibers, while the total body fat is increasing
• aside from local desaturation and elongination effects, the overall muscular fatty acid pattern does (much like in humans, by the way) mirror the dietary intake
• canola or linseed oils produce a substantial increase in the content of linolenic acid (C 18:3), and slightly increase the eicosapentaenoic (EPA, C 22:5) and docosahexaenoic (DHA, C 22:6) acid contents in pork mea
• soy, peanut, corn, and sunflower increase the content of linoleic acid (C 18:2; omega-6), increase the n-6:n-3 ratio and reduce the content of mono-unsaturated fats (MUFAs)
• fish oils or algae added to the feed substantially increases the content of EPA and DHA and thus reduce the n-6:n-3 ratio
• a high saturated fat content as in tallow (see figure 2) increases the levels of palmitic, palmitoleic, stearic and oleic acids in pork meat and reduces the PUFA:SFA ratio 
• CLA supplementation can increase the CLA content of the fatty portion of the meats (1% CLA results in 5.5 mg CLA/100g) and the adipose tissue (2% CLA yields 1,490mg CLA/100g fatty acids).

As you can see, the same rule applies for humans, pigs and, as you know from a previous SuppVersity post, mice who are fed inferior, since soy-fed salmon, as well: You are what you eat, folks!

Wallowing, roaming, routing: Work out like a pig

Since pigs make a pretty decent model of human metabolism and in view of the fact that - aside from our diets - the amount of exercise we get is one of the fundamental determinants of the total and relative levels of body fat, it should not be forgotten that "exercise" or rather the ability to range freely and be as active as any swine should be, is another determinant of the quality of the meat you are buying at the supermarket, grocery store, butcher or your local farmer. In this context, Reig et al. point out that

If you have no idea of the different cuts and location of the individual muscle, I suggest you download the "Meat Cuts Manual" from the website of the Canadian Food Agency. It's free and bilingual.

"[i]t has been reported that pigs maintained in free-range conditions in the Mediterranean forest had subcutaneous and intramuscular fats with higher monounsaturated fatty acids and lower saturated fatty acids than those pigs housed individually and receiving acorns as feed. The subcutaneous fat depth increases with exercise being 15.9 mm for exercised pigs in comparison to 11.5 mm depth for those kept in confinement. The same applies for the intramuscular fat content where 3.36% for extensive vs 1.44% for intensive raised pigs have been reported in the semimembranosus muscle." (Reig. 2013)

And if you really intend to overcomplicate things, you would also have to ask your butcher, whether the sausages you are about to buy were made of the meat of male of female pigs. After all, meat from barrows typically contain more fat and marbling and a thicker subcutaneous fat layer than meat from gilts (Armero. 1999). But let's face it: If you start stressing about things like this, the quality of your meat is probably your least problem.

If you want to know read more about epidemiological overgeneralization andthe effects of "pork" and red meat on your health (spec. the prostate) I suggest you go back to the Meat-Ology post.

So what's the bottom line, then: I guess the bottom line of the above insides is twofold. As far as you as an individual are concerned, it would be yet another argument for getting your meats (pork or whatever else) from a farm nearby, where you know what you are getting. It is yet also evidence of the fact that meticulous nutrient counting as I often see it in former calorie counters who have nor grasped the notion that "a calorie is not a calorie" is of little avail - at least if you expect to be able to calculate them as precisely as you can read them on the nutrition labels of the 90% artificial and 100% standardized convenient foods that's probably much more the answer to the question "Why are we fat?" than the non-descript statement "insulin".

In fact, the real significance of these results lies elsewhere. It concerns the way epidemiological studies are conducted (I may remind you of the metaphorical pizza salami being red meat or pork), their over-generalizing interpretations and the conclusions on what the optimal human diet should look like. So, once the next study is telling you "red meat" or "pork" is bad for you - you may want to remind yourself of some of the things you have learned in today's blogpost and ask yourself (and if you incidentally have the chance, the researchers as well): What kind of "pork" are we talking about?

References:

• Abebe W, Mozaffari MS. Role of taurine in the vasculature: an overview of experimental and human studies. Am J Cardiovasc Dis. 2011;1(3):293-311.
• Armero E,  Flores M,  Toldrá F,  Barbosa JA,  Olivet J,  Pla M,  Baselga M.Effects of pig sire types and sex on carcass traits, meat quality and sensory quality of dry-cured ham.  Journal of the  Science of  Food  and  Agriculture. 1999; 79:1147-1154.
• Enser M, Hallett K, Hewitt B, Fursey GA, Wood JD. Fatty acid content and composition of english beef, lamb and pork at retail. Meat Sci. 1996 Apr;42(4):443-56.
• Reig M, Aristoy MC, Toldra.Variability in the contents of pork meat nutrients and how it may affect food composition databases. Food Chemistry. 2013 [ahead of print]
• The China Post. Clenbuterol-tainted pork latest China food scandal. March 18, 2011. < http://www.chinapost.com.tw/china/national-news/2011/03/18/295146/Clenbuterol-tainted-pork.htm > retrieved Dec 06, 2013.

Making the Right Fish Choices: Fatty Acid Contents of 33 Different Fish Species. Plus: What Are the Implications?

Pollachius virens (Photo: Tino Strauss) is king, when it comes to the n:3/n:6 ratio, but with <1% of fat you will still be hard pressed to get tons of omega-3s from eating pollock... but is more really better, let alone necessary?

I have already broached the issue of the differences in the fatty acid composition of fish - even those of the same species - in past articles such as the one(s) on fish as a potential source of mercury in your diet (read more). When I saw the recent paper by Claudia Strobel, Gerhard Jahreis and Katrin Kuhnt in Lipids in Health and Disease, I thought that it was about time to supply you with some real data on the actual n:3/n:6 ratio of different fish and its implications for the purported health benefits and anti-obesity effects of regular fish intake. Is there a "super fish" or is it as so often a matter of "mixing and matching" to achieve the right balance?

Fish? Of course, I have fish & chips or fish sticks every other day!

I guess I don't have to tell you that both the fish part of "fish and chips", as well as the "healthy" fish sticks that are pretty popular at least among German kids, should actually be sold at the bakery, right? I mean the ratio of the bread crumb coating to the pressed fish fillets inside, is hilarious and in view of the fact that these products are 'pre-fried' with cheap vegetable oil before they end up in the freezer cabinets of supermarkets all around the world, you cannot avoid the increased (partially oxidized) omega-6 intake, even if don't (as most people do) fry them at home.

So, if the fast-food version of "fish" is not an option to gear your polyunsaturated fatty acid ratio more towards the n-3 side of things, which fish shall you go for? Well, according to the data the scientists from the Friedrich Schiller University in Jena, Germany, collected Pollachius virens is the n3:n6 king among the seven most frequently consumed fish species, which are herring, tuna, pollock, alaska pollock, salmon, rainbow trout and iridescent shark (at least according to Strobel, 2013).

Figure 1: Content of EPA & DHA, other omega-3 and the sum of omega-6 fatty acids in percent of total fat of the 33 tested species in the study; ordered according to n3:n6 ratio, fish with the highest n3:n:6-ratios on the left; note: the anchovies and sardines were in a tin with oil and while they were drained before the analysis this will have decreased the n-3:n-6 ratio (data calculated based on Strobel. 2013)

On the other hand, the total fat content of pollock (<1%) is so low that you will be hard pressed eating enough of it to elicit any significant health effects. As far as the most frequently consumed fish species go, this does bring us back to our good old friend, the salmon.

Figure 2: Comparison of fatty acid content in g/100g of wild and farmed salmon (left) and respective omega-3 to omega-6 ratios (right; based on Strobel. 2013)

Unfortunately "salmon" does not equal salmon, these days. The dripping orange stuff you can buy for a few bucks (the orange color is artificially added to the feed by the way) at every supermarket, for example, is farmed salmon and contains only 2-3x more omega-3 fatty acids than omega-6s. The reddish, lean cuts of wild salmon on the other hand, have a 12-13x higher relative omega-3 content and in fact almost no omega-6 fatty acids (0.05g / 100g). With 0.53g /100g omega-3 fatty acids, wild salmon is yet just like pollock not the "bulk" source of omega-3 fatty acids you would be looking for, if you fell for the stupid idea that you could undo the damage you are doing by eating tons of (oftentimes oxidized) omega-6 fatty acids by simply throwing an even greater amount of omega-3s into the equation.

So what do we make of all that information?

The very latest on the effects of fish consumption on body weight comes from a study in the latest issue of the British Journal of Nutrition and shows that there is no effect of higher intakes of total, lean or fatty fish on 5-year risk of becoming obese in the 344,757 male and female participants of the European Prospective Investigation into Cancer and Nutrition (Jakobsen. 2013). Now, this does not exclude the existence of non-body weight related benefits, but it certainly puts the myth of the "anti-obesity" effect of fatty fish into perspective. After all, every 10g of additional high fat fish in the diets of the female study participants was associated with a 5x more pronounced increase in body weight than an equal amount of low fat fish. The general trend towards increasing BMIs was yet countered by none of the two.

In view of the fact that we are suffering from a relative deficiency in omega-3 fatty acids, only (relative to the exubarant amount of omega-6 fatty acids the average Westerner consumes on a daily basis), I see the data presented in this post not as a "shopping guide", but rather as a means to conduct a reality check of how realistic it really is that someone who follows a no fast- and convenient-food diet and keeps a non-neurotic eye on his overall n-6 intake will benefit from omega-3 intakes in the multiple gram range.

Specifically when it comes to supplementation, previous trials such as Filaire et al. did in fact find increases in oxidative stress in perfectly healthy athletes (judo) in response to 6 weeks on 600mg EPA + 400mg DHA per day (Filaire. 2010). If you also take into consideration that these negative effects on lipid oxidation were not ameliorated by higher alpha-tocopherol (vitamin E) levels, the message this and other studies are sending is clear: The putative increase in omega-3 requirements is a result of an abnormally high intake of omega-6 fatty acids.

The easiest way to escape any negative effects while still reaping the benefits therefore is to reduce (not totally avoid!) the intake of omega-6 fats (specifically from processed foods) - full stop! If you do that by incorporating a large variety of whole foods into your diet and include grass-fed beef, dairy from pastured cows and, obviously, fish on a regular basis, you won't have to increase your intake of omega-3 fatty acids by picking the orange colored, disgustingly tasting, fat dripping farmed salmon from the super market over its delicious red wild cousin, just because it has 4.5x more omega-3 fatty acids.

Bottom line: It's food quality and fatty acid ratios that make the difference; not the absolute numbers of allegedly good and bad fats, carbs and whatever else has recently fallen victim to the over-generalization that appears to be necessary to render dietary advice suitable for the masses. If there is any one thing that's to blame for the health crisis these days, it's this kind of black-and-white thinking that's behind the overgeneralized and faulty "expert advice" which is by no means propagated exclusively via supposedly unreliable sources on the Internet.

References:

• Filaire E, Massart A, Portier H, Rouveix M, Rosado F, Bage AS, Gobert M, Durand D. Effect of 6 Weeks of n-3 fatty-acid supplementation on oxidative stress in Judo athletes. Int J Sport Nutr Exerc Metab. 2010 Dec;20(6):496-506.
• Jakobsen MU, Dethlefsen C, Due KM, May AM, Romaguera D, Vergnaud AC, Norat T, Sørensen TI, Halkjær J, Tjønneland A, Boutron-Ruault MC, Clavel-Chapelon F, Fagherazzi G, Teucher B, Kühn T, Bergmann MM, Boeing H, Naska A, Orfanos P, Trichopoulou A, Palli D, Santucci De Magistris M, Sieri S, Bueno-de-Mesquita HB, van der A DL, Engeset D, Hjartåker A, Rodríguez L, Agudo A, Molina-Montes E, Huerta JM, Barricarte A, Amiano P, Manjer J, Wirfält E, Hallmans G, Johansson I, Khaw KT, Wareham NJ, Key TJ, Chajès V, Slimani N, Riboli E, Peeters PH, Overvad K. Fish consumption and subsequent change in body weight in European women and men. Br J Nutr. 2013 Jan;109(2):353-62.
• Strobel C, Jahreis G, Kuhnt K. Survey of n-3 and n-6 polyunsaturated fatty acids in fish and fish products. Lipids Health Dis. 2013 Oct 30;11:144.